Hibschite

A variety of grossular with part of the orthosilicate ions replaced by hydroxide ions. Previously considered by some to be a discrete mineral species itself. The end-member composition is called katoite. Hibschite is now an informal intermediate composition in the Grossular-Katoite Series. Igumnovite is similar, with Cl in place of (OH).

History

Activities related to discovery and approval of the group members

Structural context

Hibschite
Crystal System isometric
a11.94—12.174 (12.0403)
b11.94—12.174 (12.0403)
c11.94—12.174 (12.0403)
alpha90
beta90
gamma90
volume1702.2—1804.26 (1745.7025)

Based on 4 measurements

Chemical context

Stoichiometric formulas

Hibschite
mindat.org
  • March 13, 2023Ca3Al2(SiO4)3-x(OH)4x(x = 0.2-1.5)
mineralogy.rocks
  • Aug. 30, 2022Ca3Al2(SiO4)3-x(OH)4x

Elements recorded on EPMA

4
Al
4
Ca
4
O
4
Si
3
H
1
D
1
F
1
Fe

Physical properties

ColorColor entities, recognized using a custom trained NER model
  • colourless
  • pale yellow
  • smoky grey
  • bluish green
    Color noteOriginal color note from the source
    Usually colourless, pale yellow, may have tints of grey, green to bluish green, also may be smoky grey to black.
    StreakStreak entities, recognized using a custom trained NER model
      Streak noteOriginal streak note from the source
      White
      Lustre
      Vitreous
      Sub-Vitreous
      Fracture
      Irregular/Uneven
      Sub-Conchoidal
      Transparency
      Transparent
      Tenacity
      brittle
      Hardness
      6.5
      Measured density
      3.06—3.25
      Calculated density
      3.28